The sideways tilt of a sailboat, pushed over by the wind in its sails.
Heel is the angle by which a sailboat leans to one side, pushed over by the wind in its sails. The keel and the boat's form resist it and push back; where the two forces balance, the boat settles at its heel angle. A boat heels to leeward, away from the wind.
How much is right
Some heel is normal and part of sailing. Beyond a point, though, it costs more than it brings:
- the boat makes more leeway and gets slower,
- weather helm grows: the boat wants to turn into the wind, and the rudder has to brake against it,
- life on board gets harder, and the risk of being knocked flat by a gust rises.
Most monohulls sail best upwind at a moderate heel. If the rail is constantly in the water, it's usually time to reduce power.
Reducing heel
Ease the mainsheet or drop the traveller to leeward in gusts, flatten the sails, move the crew to windward, and if that's not enough, reef.
Heel, roll and list
Heel comes from the wind and stays fairly steady. Rolling is the side-to-side swinging in waves, worst when running. A list is a lean that doesn't depend on the wind, for example from uneven loading.